Just before I start, the abbreviation NSEW mean – North, South, East, West. As you know I have 5 different bases, they are all of different diameter, so I will put them to the test and come up with the best diameter for my tamping style and liking.
First of all I am going to describe my tamping style and pace each of the bases exactly the same way with the same dose. I am packing the coffee just on the line for better visual result. I generally collapse the coffee twice, a decent 2-drop collapse on the grinder arms and then a light collapse on top of the doser before levelling the excess coffee back into the dosing chamber. Here is the video (under 2mb) for you to understand a little better.
My tamping has changed over this year drastically, that is why I need a tamper that will suit my current style best. As I am not tapping the side of the portafilter before my 2nd polish, so need the tamper to grab as much edge as possible with little coffee left on the inside rim of the basket. For this experiment I am using a standard 18g LaMarzocco basket, which has a dose line groove. I would much rather a synesso basket that doesn’t have the line groove, soon I will get my hands on one eventually and do this very same experiment.
I took all the photos after my tamping routine without flicking the waste so you can clearly see the excess grounds left behind. So here is my verdict…
57.7mm – Stainless steel – c-flat
This base is considerably smaller than 58.0mm and really feels that way, as soon as you put it in you can really feel the room between the basket and the tamp base. This size base is perfect if you use “NSEW” technique. Some people actually prefer their tamper to be smaller, here is a post by Mark Prince I read on coffeed a while back. I don’t use the same technique as Mark, so didn’t favour this size at all, as you can see from the picture there is a considerable amount of coffee along the rim that this base didn’t grab.
If you do decide to go with this size, I recommend you chose the c-flat base, just like mine. It will be more forgiving than others (if used properly). The shot that it pulled was great; I really like the c-flat extraction.
57.8mm – Aluminium – flat
Slightly bit bigger, from the picture you can’t really see much of an improvement on the edge. This is a flat base so I definitely do not recommend getting it smaller than 58.0mm. There is no advantage to it even if you use “NSEW” technique. The purpose of this base is to grab the edge as much as possible and at this size it has simply failed to do so. It felt very loose in the hand. The extraction results were decent but not great, due to its diameter and flatness.
58.0mm – Brass – c-flat
This base is 0.2mm bigger than previous and already you can visually spot the difference. As you can see the edge is much sharper, my concern with it was the LaMarzocco basket, the coffee gets stuck in the line, still the c-flat base is more forgiving than other bases, so it pulled a very good shot that I was happy with. I am assuming that it will pull a better shot out of the synesso basket as it doesn’t have the line in the basket. This size is the industry standard for many reasons, if you use “NSEW” technique it will suit you just fine as there is enough room between the base and the edge. And if you use my type of technique it is also a very solid performer. You can definitely find some middle ground with this base and wont go wrong by choosing it.
58.1mm – Brass – American Curve
Once again I am not too happy about the coffee getting stuck in the line and visually this photo doesn’t look much different than 58.0mm but I assure you it felt much better tamping down, much tighter, closer to the edge with less room between basket and the base. This grabs the edge nicely and is great for my technique. The shot was very solid!
58.2mm – Copper – Euro Curve
This is my favourite size, feels amazing going down on the first tamp. The diameter is just perfect and fits the basket like a glove. Right up to the edge leaving practically no coffee up on the sides of the basket. For my dosing technique it is perfect. As this was a euro curve the extraction expanded from the sides into the middle, I think I would prefer a c-flat base which is curved like “euro curve” on the sides with a flat, even extraction in the centre - expanding up onto the shower screen. The coffee tasted fantastic, so I am all for this diameter.
Choosing the right base for yourself should be decided according to your tamping technique, if you like to experiment I would suggest getting a standard 58.0 and something smaller and/or something bigger. Personally I am leaning towards 58.2 at the moment. The curve is also a very important choice and also depends on what style of tamping you use. For me it would have to be a c-flat base or a curved base. The flat base is also great but for me doesn’t pull a better shot over other curves, many might argue, but my experiments have proven my taste buds right, over and over again.